Multi-directional bar code reading device

ABSTRACT

A multi-directional bar code reading device for reading an object that is to be read by projecting scanning beams from many directions, includes a plurality of mirrors (2) arranged around a beam scanning unit (1) and a plurality of beam sources (3) for emitting beams toward the beam scanning unit (1). The beam scanning unit (1) is irradiated with beams generated from the plurality of beam sources (3), scanning beams are reflected by the plurality of mirrors (2) and are projected from a plurality of directions onto an object (5) to be read, and light reflected from the object (5) is detected in order to read bar codes on the object (5) to be read.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to U.S. application Ser. No. 07/598,427,filed Oct. 16, 1990.

This application is a continuation of application Ser. No. 08/446,297,filed May 22, 1995, now abandoned, which is a continuation ofapplication Ser. No. 08/206,260, filed Mar. 7, 1994, now abandoned,which is a continuation of application Ser. No. 07/950.130, filed Sep.24, 1992, now abandoned, which is a continuation of U.S. applicationSer. No. 07/662,118, filed Feb. 18, 1991, now U.S. Pat. No. 5,206,491.

BACKGROUND OF THE INVENTION

The present invention relates to a multi-directional bar code readingdevice for reading a bar code on an object that is to be read byprojecting scanning beams from many directions.

A POS system (point-of-sales data management system) has been used indepartment stores and in supermarkets in order to enhance efficiency inthe management of goods and in the check-out operation. It is desiredthat the goods and products labelled with bar codes be efficiently readout irrespective of the positions where they are placed.

In general, the problem of expediting material handling in a manner tominimize the need for human intervention still exists. Numerous systemshave been developed to achieve this end. Some of these systems require ahand held reader for special labels which are placed on the articles. Inother systems, great care must be taken to insure that the articles passthrough a detection zone with their labels properly positioned andoriented with respect to a reader.

In data acquisition systems developed for retail point-of-saleapplications, the typical way in which data entry is effected requiresthat a clerk read sales data from a ticket associated with each item ofmerchandise and then manually enter this data into the system using akeyboard. Therefore, a hand-held reader has been developed for scanningmachine readable optical and magnetic codes applied to tickets pursuantto entering the sales data into the system. As is apparent, theautomatic entry of sales data encoded in machine readable form can beeffected more rapidly and accurately than manual entry via a keyboard.

The ultimate approach to the problem of data entry in this area appearsto be the use of a fixed scanner for reading from a distance machinereadable, optically encoded data from a ticket attached to each item.This approach frees the clerk from the task of having to manipulate areader and also considerably eases the problems of variations inscanning rate inherent in hand scanning.

According to a fixed type scanner that has heretofore been used insupermarkets and similar stores, the directions in which the scanningbeams are projected are limited to just straight up from one surface orupward tilted directions. Therefore, an operator must carry out acumbersome operation in which he makes sure the position or surfacewhere the bar codes are attached to the goods, directs the device towardthe reading direction and executes the reading operation. Moreover, evenwhen the bar codes attached to the articles on a production line are tobe automatically read out, the articles have to be so arranged inadvance that the positions or surfaces where the bar codes are labelledare oriented in a predetermined direction, causing such problems as thefacility of handling bulky objects and difficulty involved in arrangingproducts having dissimilar sizes on the same line.

From the above discussion of a fixed type bar code reading device, it isnecessary to provide an appropriate optical scanner device including thefollowing:

1. A beam scanning unit; a plurality of reflecting mirrors arrangedaround the beam scanning unit; and a plurality of beam sources foremitting beams toward the beam scanning unit.

2. In item 1, the beams are controlled so as to be emitted from only oneof the plurality of beam sources.

3. In the beam scanning unit of the item 1, both beam reflectingsurfaces and beam non-reflecting surfaces are mounted on a scanningmirror to always emit only one scanning beam in the beam scanning unit.

With regard to the above item 3, a prior art U.S. Pat. No. 3,818,444(Filed Jun. 29, 1972), was disclosed on Jun. 18, 1974, by Richard A.Connell (assignee: Pitney-Bowes, Inc.), entitled "Optical Bar CodeReading Method and Apparatus Having an X Scan Pattern".

4. In an optical scanning unit, a plurality of optical systems areexclusively controlled to always emit a scanning beam from only oneoptical system selectively.

This method includes: effecting scanning processes from a plurality ofdirections to select a beam from only one optical source by means of anoperation of mirrors, selecting a beam mechanically by mirrors, and soforth.

SUMMARY OF THE INVENTION

The object of the present invention is to easily read bar codes withoutbeing affected by the position at which they are attached to an objectthat is to be read, by irradiating a beam scanning unit, e.g., apolygonal mirror, with beams emitted from a plurality of beam sources,and reflecting the formed scanning beams using a plurality of mirrors sothat the beams are projected from a plurality of directions onto theobject to be read.

A beam scanning unit scans the beams that are emitted in order to formthe scanning beams. Mirrors are arranged to surround the beam scanningunit and reflect the scanning beams so that they are projected onto anobject that is to be read. Beam sources generate the beams.

In accordance with the present invention, there is provided amulti-directional reading device for reading an object that is to beread by projecting scanning beams from many directions, including: aplurality of mirrors arranged around a beam scanning unit and aplurality of beam sources for emitting beams toward the beam scanningunit, wherein the scanning unit is irradiated with beams generated fromthe plurality of beam sources, scanning beams reflected in a scanningmode are reflected by the plurality of mirrors and are projected from aplurality of directions onto an object to be read, and light returnedafter being reflected is detected in order to read bar codes on theobject to be read, and the beam is exclusively emitted from only one ofthe plurality of beam sources.

Therefore, bar codes are easily read out without being affected by theposition at which they are attached to the object to be read, byirradiating a beam scanning unit with beams emitted from a plurality ofbeam sources, and reflecting the formed scanning beams using a pluralityof mirrors so that they are projected from a plurality of directionsonto the object that is to be read.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a prior art fixed type scanner;

FIG. 2A is a perspective view and FIG. 2B is a cross-sectional viewshowing, respectively, the constitution of an embodiment in accordancewith the present invention;

FIG. 3A is a perspective view where the windows are nearly at rightangles to each other and FIG. 3B is a sectional view of themulti-directional bar code reading device shown in FIG. 3A;

FIG. 4A is a perspective view of another embodiment of themulti-directional reading device in which four windows are providedsymmetrically on a plane with the polygonal mirror at the center, andFIG. 4B is a sectional view of the device shown in FIG. 4A;

FIG. 5A is a block diagram illustrating how the beam source is turned onaccording to the present invention, and FIG. 5B is a diagram of theprocess of turning on the laser beam source;

FIGS. 6A, 6B and 6C are drawings showing other embodiments of opticalscanning device in accordance with the present invention, wherein FIG.6A and FIG. 6B are a perspective view and a cross-sectional view,respectively, of the multi-directional optical scanning device for barcode reading, having a specified beam scanning unit, and wherein FIG. 6Cis a perspective view showing still another embodiment having a singlebeam source and a multi-beam generation mechanism, provided with aspectroscope and lens system, in accordance with the present invention;

FIG. 7A and FIG. 7B are a top view and a perspective view of anembodiment of a specified beam scanning unit having beam reflectingsurfaces and beam non-reflecting surfaces in accordance with the presentinvention;

FIG. 8 is a perspective view showing a rotary polygon mirror and theoperation thereof as another embodiment;

FIG. 9 is a cross-sectional view of an optical scanning device using thepolygon mirror in FIG. 8 of an embodiment in accordance with the presentinvention;

FIG. 10 is a perspective view of the rotary polygon mirror in FIG. 9;

FIGS. 11A and 11B illustrate each front view of the reflecting portionin FIG. 10; and

FIGS. 12A, 12B and 12C illustrate multifarious patterns which the laserbeam scans when θ2 changes, when θ1 changes and when θ1 and θ2 change.

As FIG. 13 is a sectional view showing an embodiment using a rotarypolygon mirror having two or more reflecting surfaces in accordance withthe present invention; and

FIG. 14 is a perspective view showing an embodiment of a rotary polygonmirror having three reflecting surfaces.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the prior art drawings, the present invention will bedescribed in detail by clarifying the differences between the presentinvention and the prior art.

FIG. 1 is a perspective view showing a prior art fixed type scanner.Reference numeral 1 denotes a scanner, 11 scanning beams, 13 a window,and 51 an object or a product. The direction in which the scanning beamsare projected is limited to just straight up from one surface or uppertilted directions. An operator must carry out cumbersome operations inwhich he makes sure the position or surface where the bar codes areattached to the goods, directs the device toward the reading directionand effects the reading operation. Moreover, even when the bar codesattached to the articles on a production line are to be automaticallyread out, the object has to be so arranged in advance that the positionsor surfaces where the bar codes are labelled are oriented in apredetermined direction.

FIG. 2(A) is a perspective view and FIG. 2(B) a cross-sectional viewshowing the constitution of an embodiment of the present invention.

Referring to FIGS. 2(A) and 2(B), the beam scanning unit 1 scans thebeams that are emitted to form the scanning beams and is comprised, inthis case, of a polygonal mirror, for example, a polyhedral mirror thatis rotatable.

Mirrors 2 are arranged around the beam scanning unit 1 and constitute aplurality of pattern mirrors. The scanning beams 11 reflected by themirrors 21A, 21B are projected through windows 13A, B onto the object 51that is to be read. Here, the mirrors 21 are provided in a numbercorresponding to the number of beam sources 3 such that the scanningbeams 11 are projected through the respective windows 13 onto the object51 to be read.

The beam sources 3 (3A, 3B) generate beams and serve as laser beamsources.

The light-receiving elements 4 (4A, 4B) receive light reflected from theobject 51 to be read and convert it into an electric signal.

The object 51 to be read is goods or a product to which bar codes areattached so as to be read.

A control unit 6 rotates the beam scanning unit 1 in order to form thescanning beams and further works to exclusively turn on the plurality ofbeam sources 3.

Next, described below is the operation of the constitution of FIGS.2(A), 2(B) which consist of two sets of beam sources 3, mirrors 2, 21and 22, lenses 23 and light-receiving elements 4 for one beam scanningunit 1.

The beams generated from the two beam sources 3 are permitted to fall onone beam scanning unit 1 from opposite directions.

The beam scanning unit 1 rotates and scans the beams emitted from thetwo beam sources 3A, 3B to form the scanning beams 11. The thus formedscanning beams 11 are reflected by the mirrors 21A, 21B and areprojected through windows 13A and 13B and from different directions ontothe object 51 that is to be read. Therefore, the object 51 to be read iswidely scanned from just underneath and from both sides thereof by aplurality of scanning beams 11 that are successively projected indifferent directions from the plurality of mirrors through the window13A and 13B by a plurality of scanning beams 11 that are successivelyprojected in different directions from the plurality of mirrors throughthe window 13B, and whereby the bar codes attached thereto can bescanned over a wide range.

The light reflected from the object 51 to be read is detected by thelight-receiving elements 4 through mirrors 21, beam scanning unit 1,focusing lenses 23A and 23B, and reflectors 22A and 22B. Bar codesattached to the object 51 to be read are then read. In this case, thecontrol unit 6 controls the rotation of the beam scanning unit 1 andfurther works to exclusively turn on only one of the beam sources 3 at atime, so that the scanning beams will not produce noise which will bemixed into the other light-receiving element 4.

Due to the above-mentioned operation and due to the provision of twosets of beam sources 3, mirrors 21 and, 22, lenses 23 andlight-receiving elements 4 for one beam scanning unit 1, the scanningbeams are projected from different directions onto the object 51 to beread, and it is possible to easily read the bar codes by the scanningover a wide range irrespective of the position of the object 51 to beread.

Described below with reference to FIG. 2A and 2B is the constitutionaccording to another embodiment of the case when the scanning beams areprojected onto the goods (object 51 to be read) from nearly right-angledirections.

FIG. 3(A) is a perspective view where the windows 13A and 13B are nearlyat right angles to each other, and the scanning beams are projected ontothe goods 51 through the windows 13A and 13B in order to read bar codesattached to the goods 51.

FIG. 3(B) is a sectional view of the multi-directional reading deviceshown in the perspective view of FIG. 3(A).

In FIG. 3(B), two sets of laser beam sources 31A and 31B, patternmirrors 21, windows 13A and 13B, and light-receiving elements 4 areprovided at nearly right-angle directions for one polygonal mirror 12.Due to this constitution, the scanning beams are projected onto thegoods 51 through the windows 13A and 13B at positions nearly at rightangles to each other, and the returned light after reflection isdetected by the light-receiving elements 4 in order to read the barcodes. Therefore, the scanning is effected over a wide range such asfrom under and from the sides of the goods 51 to easily read the barcodes. During the scanning, the laser beam source 31A or the laser beamsource 31B is controlled to be turned on exclusively.

FIG. 4A and 4B show a constitution in which four sets of laser beamsources 3A to 3D, pattern mirrors 21A to 21D, windows 13A to 13D andlight-receiving elements 4 are arranged on a plane with one polygonalmirror 12 at the center.

FIG. 4(A) is a perspective view of the multi-directional reading devicein which four windows 13A to 13D are provided symmetrically on a planewith the polygonal mirror 12 at the center.

FIG. 4(B) is a sectional view of the multi-directional reading deviceshown in the perspective view of FIG. 4(A).

In FIG. 4(B), four sets of laser beam sources 3A to 3D, pattern mirrors21A to 21D, windows 13A to 13D, and light-receiving elements 4A to 4Dare provided symmetrically on a plane with one polygonal mirror 12. Dueto this constitution, the scanning beams are projected onto the goodsthrough the windows 13A to 13D, i.e., from the four directions, and thereturned light after being reflected is detected by the light-receivingelements 4 in order to read bar codes. Therefore, the scanning iseffected over a wide range from four directions under the goods 51 toeasily read the bar codes. During the scanning, the four laser beamsources 3A to 3D are controlled so that only one is turned on at a time.

FIGS. 5A and 5B form a diagram illustrating how the beam source isturned on according to the present invention.

In FIG. 5(A), the control unit 6 is the one shown in FIG. 1 which worksto scan the beam scanning unit (polygonal mirror) 1 and to exclusivelyturn on only one of the plurality of beam sources (laser beam sources)3.

FIG. 5(B) shows a diagram of the process of turning on the laser beamsource. This turn-on chart is for the case where there are two sets oflaser beam sources 3A, 3B, or 31A, 31B that are shown in FIGS. 3A, 3B,4A and 4B. Here, symbol T represents a time in which the beam source isturned on/turned off (ON/OFF). Two sets of laser beam sources arealternatingly turned on after every time T, and the reflected light isdetected by the light-receiving elements to read the bar codes, whileeliminating the noise (interference) caused by the other scanning beam.Even when two or more sets of laser beam sources are used, the operationis similarly controlled to exclusively turn on only one of the laserbeam sources in turn.

According to the present invention as described above, the scanningbeams formed by one beam scanning unit (e.g., polygonal mirror) which isirradiated with beams emitted from a plurality of beam sources, arereflected by a plurality of mirrors and are projected from a pluralityof directions onto the object to be read. Therefore, the bar codes canbe easily read without being affected by the position at which they areattached to the object to be read. In particular, since only one beamscanning unit (e.g., polygonal mirror) is generally used, it is possibleto realize the device with a simple structure, a small size, and at areduced cost. Moreover, since the goods and products can be read outirrespective of the positions at which the bar codes are attachedthereto, the burden on the operator is reduced, and management ofproducts can be carried out automatically and easily in a manufacturingplant or the like based upon the bar codes.

A further embodiment in accordance with the present invention will nowbe described with reference to FIGS. 6(A), 6(B) and FIGS. 7(A), 7(B).

In FIGS. 6(A) and 6(B), an optical scanning device has the sameconstitution as that in FIGS. 2(A) and 2(B), except for a beam scanningunit 1. The beam scanning unit 1 has beam reflection surfaces 15 andbeam non-reflection surfaces 17 both of which are rotatable around anaxis in order to form a scanning beam 11 by reflecting the beam 30 byscanning unit 1 and mirrors 21, to produce only one of the beams 30emitted from beam sources 3A, 3B. Mirrors 2 are provided to correspondto the beam sources 3 such that a scanning beam 11 formed by the beamscanning unit 1 is reflected by the mirrors and is projected onto theobject 5 to be read.

It is therefore made possible to easily read bar codes irrespective ofthe position at which they are attached to the objects 5 to be readwhile eliminating the effects of interfering light such as otherscanning beams. It is also possible to provide reading apparatus havinga simple constitution in which a beam scanning unit 1 is provided withbeam reflecting surfaces 15 and beam non-reflecting surfaces 17, andonly one scanning beam 11 is formed at all times from a plurality ofbeams and is projected onto the object 5 that is to be read.

The constitution and operation of an embodiment of the present inventionwill now be described in detail in conjunction with FIGS. 6(A) and 6(B).

Referring to FIGS. 6(A) and 6(B), the beam scanning unit 1 scans thebeams that are emitted to form a scanning beam 11 and is comprised, inthis case, of a polygonal mirror (a polyhedral mirror that isrotatable). The beam scanning unit 1 has beam reflecting surfaces 15 andbeam non-reflecting surfaces 17, and forms a scanning beam 11 byreflecting, in a scanning mode, only one beam at all times from amongthe beams emitted from the plurality of beam sources 3.

Mirrors are arranged around the beam scanning unit 1 and constitute aplurality of pattern mirrors 21. The scanning beams 11 are reflected bythe set of mirrors and are projected through windows 13 onto the object5 that is to be read. Here, the number of mirrors corresponds to thenumber of beam sources 3 such that a scanning beam 11 is projected atall times through each of the windows 13 onto the object 5 to be read.

The beam sources 3 generate beams 30 and serve as laser beam sources.

The light-receiving elements 4 receive light reflected from the object 5to be read and convert it into an electrical signal.

The object 5 to be read is, for example, goods or a product to which barcodes are attached to be read out.

A control unit 6 rotates the beam scanning unit 1 in order to form thescanning beam 11.

Referring to FIG. 6(C), another embodiment is shown in which an opticalsystem in conjunction with a light source 3S, a spectroscope S andmirrors L1 . . . L4 is used to emit light beams from a plurality ofdirections.

The beam scanning unit 1 will now be described in detail in conjunctionwith FIGS. 7(A) and 7(B). As shown in the perspective view of FIG. 7(B),the beam scanning unit 1 is constituted by beam reflecting surfaces 15that reflect, in a scanning mode, a beam emitted from the beam sources,and a beam non-reflecting surfaces 17 which do not reflect the incidentbeam emitted from the beam sources (or which reflects the beams in adirection other than the directions of mirrors 2 so as not to become asource of noise). The beam reflecting surfaces 15 and the beamnon-reflecting surfaces 17 are alternately provided, for example, asshown in FIG. 7(A), so that light beams from the beam source 3A and thebeam source 3B are alternately reflected thereby to form a scanning beam31.

Next, described below is the operation of the constitution of FIGS. 7Aand 7B wherein the beam scanning unit 1 has six surfaces, i.e., threebeam reflecting surfaces 15 and three beam non-reflecting surfaces 17,and further has two sets of beam sources 3, mirrors, and light-receivingelements 4.

(1) The beams generated from the two beam sources 3 are permitted tofall on the beam scanning unit 1 from opposite directions.

(2) The beam scanning unit 1 rotates and scans the beams 30 emitted fromthe two beam sources 3A, 3B to form a first alternating scanning beam.The reflected scanning beam is reflected by the mirrors and is projectedonto the object to be read through the windows in different alternatingdirections. Therefore, the object to be read is scanned from underneathand from both sides by the second scanning beam 32 that is projected indifferent directions from the plurality of mirrors via the windows, sothe bar code attached thereto can be easily scanned.

(3) The light reflected from the object to be read is detected by eitherthe light-receiving element, via mirrors, beam scanning unit, focusinglenses, and reflectors. A bar code attached to the object to be read isthen converted to electrical signals.

By the above-mentioned operation and the provision of the beam scanningunit 1 having beam reflecting surfaces 15 and beam non-reflectingsurfaces 17, as well as two sets of beam sources, mirrors, andlight-receiving elements, only one scanning beam is always projectedfrom different directions onto the object to be read, so that a bar codecan be easily read irrespective of the position of the object to beread. Moreover, it is possible to eliminate the effect of interferencecaused by other scanning beams by using a device having a simpleconstitution.

Even when there are two or more beam sources, only one scanning beam ata time is reflected by the beam scanning unit 1 and then projected ontothe object to be read to thereby eliminate the negative effects causedinterference from other light. Of the beam reflecting surfaces and thebeam non-reflecting surfaces of the beam scanning unit, the beamnon-reflecting surfaces are so designed as to not reflect the beam.Here, however, the beam non-reflecting surfaces may be so designed as toreflect the beam in a direction that does not meet the mirrors, so thatthe beam is not projected onto the object to be read, and so that thebeam is not mixed into the optical system to hinder the reading of a barcode.

According to the present invention as described in the foregoingembodiments, the beam scanning unit is provided with beam reflectingsurfaces and beam non-reflecting surfaces, and only one beam is formedat all times from the beams emitted from the plurality of beam sources,and that beam is projected onto the object to be read. Therefore, thebar codes can be easily read irrespective of the position at which theyare attached to the object to be read, while eliminating the effects oflight interference caused by other scanning beams at the time ofreading, using an apparatus having a simple constitution.

Another embodiment in accordance with the present invention will now bedescribed with reference to FIGS. 8 to 14.

In a conventional multi-directional bar code reading device, a largenumber of components are needed.

These components are as follows:

a rotatable polygon mirror,

a reflecting mirror of the rotatable polygon mirror,

a holographic disc, and

reflecting portions formed of a plurality of reflecting mirrors.

These many components make the cost high and miniaturization difficult.Also, an increase in a beam pattern length leads to an increase in thesize of a reflecting mirror.

FIG. 8 is a perspective view of an embodiment of the present invention.In FIG. 8, reference numeral 121 denotes a light source emitting a lightbeam 122, and 130 a rotary polygonal mirror having a plurality ofreflection portions 135 for reflecting the light beam 122 from the lightsource 121 onto a bar code 140. The number of reflecting planes 131,132, . . . is not limited to only two.

The light beam 122 is reflected from a first reflecting plane 131 of thereflecting portion 135 and then reflected from a second reflecting plane132 to scan the bar code 140. Since at least two reflecting planes 131and 132 are provided in each face of each reflecting portion 135 toobtain a multi-directional scanning pattern, multi-directional scanningbeams are scanned on to the bar code in accordance with the rotation ofthe rotary polygonal mirror 130.

FIG. 9 is a cross-sectional view of an optical scanning device of anembodiment in accordance with the present invention. In FIG. 9 referencenumeral 151 denotes a casing of the device, 152 a reading window mountedon the top of the casing 151, 153 a light source emitting a laser beam,154 a small mirror for changing a transmission direction of the laserbeam, 155 a rotary polygonal mirror, 157 a bar code attached to anarticle 158, 159 a condenser lens for collecting laser beams, and 160 aphotodetector for detecting collected laser beams.

FIG. 10 is a perspective view of the rotary polygonal mirror in FIG. 9.A plurality (in this case, 6) of reflection portions 161 are provided onthe rotary polygon mirror 155 and two reflecting planes 162, 163 areprovided for each of the reflecting portions 161.

FIG. 11(A) and 11(B) illustrate a front view of the reflecting portionin FIG. 10 and a side view in FIG. 11(A), respectively.

In FIG. 11(A), when a boundary between a reflecting plane 162 and areflecting plane 163 forms an angle θ1 with a rectilinear line 164 (arotary axis of the rotary polygon mirror 155), the polygonal mirror isformed such that the values of θ1 are different for each reflectingplane.

In FIG. 11(B) which is a side view of FIG. 11(A), when the reflectingplane 162 forms an angle θ2 with the reflecting plane 163, the value ofθ2 is also different for each reflecting portion 161.

In FIG. 9, a transit direction of a laser beam emitted from a lightsource 153 is changed by a small mirror 154 to be directed to the rotarypolygon mirror 155, whereby the laser beam is reflected from thereflecting plates 162 and 163 of the reflecting portion 161 and thenscanned onto the bar code 157 of the article 158 through the readingwindow 152.

When the angle θ1 of each reflecting portion 161 in the rotary polygonalmirror 155 is constant and only the angle θ2 changes at each reflectingportion 161, the pattern which the laser beam scans on the bar code 157is shown in FIG. 12(A). When the angle θ2 is constant and only the angleθ1 changes at each reflecting portion 161, the pattern which the laserbeam scans on the bar code 157 is shown in FIG. 12(B). When both of theangles θ1 and θ2 change, a multi-directional scanning pattern is formedas shown in FIG. 12(C).

A light reflected from the bar code 157 is reflected by the rotarypolygon mirror 155, collected by the collecting lens 159, andtransmitted to the photodetector 160. In the photodetector 160, thelaser beam is converted into an electriced signal and is decoded as abar code signal through an A/D convertor and a demodulator (both notillustrated).

This constitution makes it possible to obtain a multi-directionalscanning pattern, using only a rotary polygonal mirror 155. Therefore,the use of a holographic disk and many reflecting mirrors is notnecessary resulting in lower cost. When the polygon mirror is made of amolded resin and the reflecting plane is formed by aluminum evaporation,the cost can be further decreased. Since the number of reflections ofthe laser beam is reduced, a loss of light energy can also be reducedand a low output light source may be utilized.

FIG. 13 is a cross-sectional view of another embodiment of the presentinvention. The shape of the rotary polygon mirror 175 is aquasi-hexagonal cylinder with a skylight. On the inner peripheral planeof the rotary polygon mirror 175, a plurality of reflecting portions 171(in this case, 6) are provided. Pairs of two reflecting planes 172, 173are provided for each reflecting portion 171.

In the same way as in FIG. 9, the reflecting planes 172, 173 are formedso that a multi-directional scanning pattern may be obtained forscanning the article 158. The constitution of this embodiment isadvantageous in that by using only a rotary polygonal mirror amulti-directional scanning pattern can be produced, and it is notnecessary to provide a hologram disk and many reflecting mirrors.Therefore, miniaturization of the device and a large cost reduction ispossible.

As shown in FIG. 14, three reflecting planes 182, 183, 184 may beprovided for the reflecting portion 181, if necessary.

We claim:
 1. A bar code reading device for reading a bar code on anobject, comprising:means for providing a light beam; means for splittingthe light beam into a plurality of light beams; means for producingscanning beams from the light beams split by said means for splittingthe light beam; windows; and means for detecting a light beam diffusedby the coded bars, said means for producing scanning beams including:arotary polygonal mirror having a plurality of reflecting portions forreflecting the light beam from said means for providing a light beam;and pattern mirrors for reflecting the light beam reflected by saidrotary polygonal mirror, to project a plurality of scanning patternsthrough said windows respectively onto different portions of an object,each of the scanning patterns including a plurality of intersectingscanning lines.
 2. A bar code reading device according to claim 1,wherein said pattern mirrors are divided into pattern mirror groups,each of which includes a plurality of said pattern mirrors, and whereineach of said pattern mirror groups produces a scanning pattern to beprojected through one of said windows onto different portions of anobject.
 3. A bar code reading device according to claim 1, wherein saidmeans for producing scanning beams produces the scanning patterns one ata time.
 4. A bar code reading device for reading a bar code on anobject, comprising:a light source for providing a light beam; opticalsplitting means for splitting the light beam into a plurality of lightbeams, each of the light beams split by said optical splitting meansbeing projected in a different direction; scanning means for producingscanning beams from each of the light beams, said scanning meansreflecting said scanning beams in different directions; pattern mirrorsfor reflecting the scanning beams from said scanning means and forprojecting a scanning pattern including a plurality of intersecting scanlines, each of said pattern mirrors corresponding to and positionedadjacent to a corresponding one of the scanning beams; and windows, eachfor projecting a scanning pattern reflected from a corresponding one ofsaid pattern mirrors, each of said windows corresponding to one of saidpattern mirrors, said windows positioned so that the scanning patternsprojected from the respective pattern mirrors are irradiated throughsaid windows onto different portions of an object.
 5. A bar code readingdevice for reading a bar code on an object, comprising:scanning meansfor reflecting in different directions a plurality of light beamsirradiated from a plurality of directions to produce a scanning beamfrom each of the light beams; at least one first window arranged in afirst direction; at least one first pattern mirror positioned adjacentsaid first window and formed by a plurality of mirrors, for reflectingone of the scanning beams from said scanning means and irradiating thescanning beam through said first window to form a scanning patternincluding a plurality of intersecting scan lines; at least one secondwindow arranged in a second direction substantially perpendicular tosaid first direction; and at least one second pattern mirror positionedadjacent said second window and formed by a plurality of mirrors, forreflecting one of the scanning beams from said scanning means andirradiating the scanning beam through said second window to form ascanning pattern including a plurality of intersecting scan lines.
 6. Amulti-directional bar code reading device coupled to a beam source,comprising:scanning means for reflecting and scanning a beam emitted bythe beam source to produce scanning beams, said scanning means includinga rotating polygonal mirror; and first and second windows from which thescanning beams produced by said scanning means are respectivelyprojected; said first window and said second window being disposed so asto be approximately perpendicular to one another, the scanning beamprojected from said first window and the scanning beam projected fromsaid second window being projected onto different portions of an objectcarrying a bar code.
 7. A multi-directional bar code reading devicecoupled to a beam source, comprising:a first window; a second windowapproximately perpendicular to said first window; a polygonal mirrorwhich reflects a beam emitted from the beam source and projects firstand second scanning beams; first reflection means for reflecting thefirst scanning beam from said polygonal mirror and projecting the firstscanning beam onto an object carrying a bar code; and second reflectionmeans for reflecting the second scanning beam from said polygonal mirrorand projecting the second scanning beam from said second window onto anobject carrying a bar code, said polygonal mirror being positionedbetween said first reflection means and said second reflection means. 8.A multi-directional bar code reading device according to claim 7,wherein said polygonal mirror has an axis of rotation which is inclinedwith respect to each of said first and second windows.
 9. Amulti-directional bar code reading device according to claim 8, whereinthe beam source includes a first beam source, which projects a beam in afirst direction, and a second beam source, which projects a beam in asecond direction which is perpendicular to the first direction.
 10. Amulti-directional bar code reading device coupled to a beam source,comprising:first and second windows; a polygonal mirror for reflecting abeam emitted from the beam source to generate first and second scanningbeams in first and second directions, respectively; a first patternmirror for reflecting the first scanning beam from said polygonal mirrorto produce a first scanning pattern and projecting the first scanningpattern from said first window onto an object carrying a bar code; asecond pattern mirror for reflecting the second scanning beam from saidpolygonal mirror to produce a second scanning pattern and projecting thesecond scanning pattern from said second window onto an object carryinga bar code; and detection means for detecting a beam which is reflectedfrom the object, the reflected beam corresponding to the first scanningpattern projected from said first window entering said reading devicefrom said first window, the reflected beam from the second scanningpattern projected from said second window entering said reading devicefrom said second window, wherein said detection means includes a firstdetection means for detecting the reflected beam incident through saidfirst window, and a second detection means for detecting the reflectedbeam incident through said second window.
 11. A multi-directional barcode reading device according to claim 10, further comprising:firstlight converging means for converging the reflected beam incidentthrough said first window in said first detection means; and secondlight converging means for converging the reflected beam incidentthrough said second window in said second detection means.
 12. Amulti-directional bar code reading device coupled to a beam source,comprising:means for generating first and second scanning beams in firstand second directions from first and second light beams, respectively, afirst pattern mirror which reflects the first scanning beam to produce afirst multi-directional scanning pattern; a first window for projectingthe first multi-directional scanning pattern in a first direction; asecond pattern mirror which reflects the second scanning beam to producea second multi-directional scanning pattern; and a second window forprojecting the second scanning pattern in a second direction, the firstand second multi-directional scanning patterns striking differentportions of an object carrying a bar code, and the first and secondmulti-directional scanning patterns being projected alternately, withsaid first and second windows being at right angles to one another, andthe two scanning beams being associated with a common scanning mirror.13. A multi-directional bar code reading device, comprising:means forgenerating first and second scanning beams in first and seconddirections from first and second light beams, respectively; a firstpattern mirror which reflects the first scanning beam to produce a firstmulti-directional scanning pattern; a first window for projecting thefirst multi-directional scanning pattern in a first direction; a secondpattern mirror which reflects the second scanning beam to produce asecond multi-directional scanning pattern; and a second window forprojecting the second scanning pattern in a second direction, the firstand second multi-directional scanning patterns striking differentportions of an object carrying a bar code, and the first and secondmulti-directional scanning patterns being projected alternately, whereinsaid generating means is a polygonal mirror having a reflective surfacewhich reflects the beam and a nonreflective surface which does notreflect the beam.
 14. A multi-directional bar code reading devicecoupled to a beam source, comprising:means for generating first andsecond scanning beams in first and second directions from a beam emittedby the beam source; a first pattern mirror which reflects the firstscanning beam to produce a first scanning pattern; a first window forprojecting the first scanning pattern in a first direction; a secondpattern mirror which reflects the second scanning beam to produce asecond scanning pattern; and a second window for protecting the secondscanning pattern in a second direction, the first and second scanningpatterns striking different portions of an object carrying a bar code,and the first and second scanning patterns being projected alternately,wherein said generating means is a polygonal mirror having a reflectivesurface which reflects the beam and a non-reflective surface which doesnot reflect the beam, and wherein said polygonal mirror receives firstand second beams from different directions from the beam source, andwherein said polygonal mirror alternately reflects the first beam andthe second beam.
 15. A multi-directional bar code reading deviceaccording to claim 14, further comprising control means for turning thebeam source on and off to produce the first and second beamsalternately.
 16. A multi-directional bar code reading device,comprising:first, second, third and fourth beam sources for producingfirst, second, third and fourth beams; a polygonal mirror having aplurality of reflective surfaces for reflecting said first, second,third and fourth beams to generate scanning beams; first, second, thirdand fourth reflection means for reflecting the scanning beamscorresponding to the first, second, third and fourth beams,respectively; a first window which projects the reflected scanning beamcorresponding to the first beam and which receives a corresponding beamreflected from an object; a second window which projects the reflectedscanning beam corresponding to the second beam and which receives acorresponding beam reflected from the object; a third window whichprojects the reflected scanning beam corresponding to the third beam andwhich receives a corresponding beam reflected from the object; and afourth window which projects the reflected scanning beam correspondingto the fourth beam and which receives a corresponding beam reflectedfrom the object, the scanning beams projected from said first, second,third and fourth windows striking different portions of an objectcarrying a bar code.
 17. A multi-directional bar code reading deviceaccording to claim 16, wherein the first beam source, said firstreflection means and said first window form a first unit, the secondbeam source, said second reflection means and said second window form asecond unit, the third beam source, said third reflection means and saidthird window form a third unit, and the fourth beam source, said fourthreflection means and said fourth window form a fourth unit, and whereinsaid first, second, third and fourth units are positioned symmetricallywith respect to one another about said polygonal mirror.
 18. A bar codereading device for reading a bar code on an object with a light beam,comprising:a rotary polygonal mirror for reflecting a plurality of lightbeams and producing a plurality of scanning beams, said plurality oflight beams being projected onto said polygonal mirror from differentdirections, the scanning beams being respectively related to the lightbeams; a plurality of windows; and a plurality of pattern mirrorspositioned to reflect the plurality of scanning beams and to project aplurality of scanning patterns through said windows onto differentportions of an object.
 19. A bar code reading device according to claim18, wherein each of the scanning patterns is the same.
 20. A bar codereading device according to claim 18, wherein said pattern mirrors aredivided into groups, with each of said scanning beams being projectedonto a corresponding one of the groups of pattern mirrors.
 21. Amulti-directional code reading device, comprising:a plurality ofwindows; a polygonal mirror for reflecting a plurality of incident beamswhich are incident on said polygonal mirror from different directions,to generate a plurality of scanning beams, wherein each of the scanningbeams is related to each of the incident beams, respectively; aplurality of pattern mirror sets respectively corresponding to saidscanning beams from said polygonal mirror and said windows, each patternmirror set producing a scanning pattern and projecting from the windowcorresponding to the pattern mirror set onto an article carrying a code,wherein said pattern mirrors project a scanning pattern that is composedof a plurality of scanning lines which are scanned in four differentdirections; and a detector positioned to detect a beam which isreflected from the article.
 22. A device for reading a code on anobject, comprising:a rotary polygonal mirror for reflecting a pluralityof light beams and producing a plurality of scanning beams, saidplurality of light beams being projected onto said polygonal mirror fromdifferent directions, the scanning beams being respectively related toeach of the light beams; a plurality of windows; and a plurality ofpattern mirrors positioned to reflect the plurality of scanning beamsand to project a plurality of scanning patterns through said windowsonto different portions of an object.
 23. A bar code reading device forreading a bar code on an object, said device comprising:a light sourceto emit a light beam; a optical system to receive the emitted light beamand to provide a first light beam and a second light beam; a singlerotary polygonal mirror having a plurality of mirror planes, to scan thefirst light beam, which is emitted towards the rotary polygonal mirror,from a first direction to produce a first scanning beam, and to scan thesecond light beam, which is emitted towards the rotary polygonal mirror,from a second direction to the rotary polygonal mirror to produce asecond scanning beam; a first group of mirrors which includes aplurality of reflecting mirrors, and which reflect the first scanningbeam to form a first scan pattern including a plurality of intersectingscan lines; a second group of mirrors which includes a plurality ofreflecting mirrors, and which reflect the second scanning beam toproduce a second scan pattern including a plurality of intersecting scanlines; a first window placed in a horizontal direction; and a secondwindow placed in a vertical direction; wherein scan lines forming thefirst scan pattern and the second scan pattern are projected from thefirst window and second window, respectively; and wherein the scan linesprojected from the first window are projected in an upward direction,and the scan lines projected from the second window are projected in ahorizontal direction.
 24. A bar code reading device for reading a barcode on an object, said device comprising:a light source to emit a lightbeam; an optical system, to receive the emitted light beam, and toprovide a plurality of light beams; a single rotary polygonal mirrorhaving a plurality of mirror planes, to scan the light beam to produce aplurality of scanning beams; a group of mirrors disposed to surround therotary polygonal mirror, and including a plurality of reflectingmirrors, the group of mirrors reflecting the scanning beams to form aplurality of scan patterns each comprising a plurality of intersectingscan lines; a first window placed in a horizontal direction, the scanlines forming the scan pattern being projected therethrough; and asecond window placed in a vertical direction, the scan lines forming thescan pattern being projected therethrough; wherein scan lines projectedfrom the first window are projected in an upward direction, and scanlines projected from the second window are projected in a horizontaldirection.
 25. A multi-directional bar code reading device comprising:asingle rotary polygonal mirror having a plurality of mirror planes toproduce scanning beams by reflecting and scanning an incident beam; aplurality of pattern mirrors, each pattern mirror including a pluralityof mirrors, to produce scanning patterns; a first window through which afirst scanning pattern, including a plurality of intersecting scanlines, is projected to a first direction; and a second window, disposedso as to be approximately perpendicular to the first window, throughwhich a second scanning pattern, including a plurality of intersectingscan lines, is projected in a second direction, the second directionbeing approximately perpendicular to the first direction.
 26. Amulti-directional bar code reading device comprising:a single rotarypolygonal mirror having a plurality of mirror planes to produce scanningbeams by reflecting and scanning an incident beam; a plurality ofpattern mirrors; and a first window and second window disposed so as tobe approximately perpendicular to each other; wherein said patternmirrors reflect the scanning beams and produce a plurality of scanningpatterns each including a plurality of intersecting scan lines throughsaid first and second windows.
 27. A multi-directional bar code readingdevice comprising:a single rotary polygonal mirror having a plurality ofmirror planes to produce scanning beams by reflecting and scanningincident beams which are projected onto said rotary polygonal mirrorfrom different directions; a plurality of pattern mirrors; and a firstwindow and a second window disposed so as to be approximatelyperpendicular to each other; wherein said pattern mirrors reflect thescanning beams and produce a plurality of scanning patterns eachincluding a plurality of intersecting scan lines through said first andsecond windows.